The inventive concept relates to semiconductor laser devices and, more particularly, to semiconductor laser devices facilitating monolithic integration and methods of fabricating the same.
Development of complementary metal oxide semiconductor (CMOS) devices has been faced with limitations of data transfer speed and power consumption. Thus, various researches have been conducted for a technique realizing optical interconnection on a silicon wafer.
Optical transmitters, optical receivers, and optical passive devices have been applied to the optical interconnection technique on the silicon wafer through various researches. However, it may be required to develop a light source facilitating monolithic integration on a silicon substrate and not needing an external light-pumping. For satisfying the above requirement, researches have been conducted for a laser device fabricated by growing germanium on the silicon substrate.
If a germanium semiconductor laser device is fabricated on the silicon substrate, it may be difficult, due to property of silicon, to cleave the silicon substrate along a cleavage plane thereof for forming facets of both ends of a gain medium (i.e., a germanium layer). Thus, after sawing the silicon substrate, a facet polishing process may be performed. In this case, it may be difficult to monolithically integrate the laser device with and optical devices such as an optical modulator, a photo detector, and a wavelength multiplexer.